SSL-TLS Certificate Error when using Firefox v74+

Firefox as of v74.0+ should now prompt if it detects an earlier TLS release and allow you to easily enable it. See the first attachment for a sample warning popup! But keep in mind this could change as new releases are rolled out! When clicking [ Enable... ] Firefox will make a change to a NEW setting to allow the warning to be bypassed.

In the background, Firefox is simply changing a parameter found in about:config settings, as shown in the second screenshot - and listed below in the summary.

Note - it is still necessary to change the parameter...
security.tls.version.max to 3 (from 4) if you have issues.
This was posted for an earlier version of Firefox.
( Please see that article, if needed )

Summary of changes to manually set (or check)...
type about:config in the URL bar of Firefox (accept the warning and continue)
type TLS (in the search bar, not the URL bat) to show only related settings

Look for these two (and change to the values shown)...
security.tls.version.enable-deprecated TRUE  (NEW setting)
security.tls.version.max 3 (also needed, even in FF74+)

Do not make these changes without just cause. But - if you encounter the error message when trying to connect to a known good site by all means, consider it.

Happy Browsing!